CCNP-5 OSPF试验1
试验拓扑：
试验要求：模拟在广播环境下，OSPF的配置与调试。
试验目的：掌握OSPF的基本配置，并且能够分析得到OSPF在广播环境下邻居发现过程，DR/BDR选举过程，定时器的时间间隔。
实验配置：
R1：
R1(config)#int f0/0
R1(config-if)#ip add 199.99.1.1 255.255.255.0
R1(config-if)#no shu
R1(config-if)#exit
R1(config)#int loop0
R1(config-if)#ip add 1.1.1.1 255.255.255.0
R1(config-if)#ip ospf network point-to-point
R1(config-if)#exit
R1(config)#router ospf 100
R1(config-router)#router-id 1.1.1.1
R1(config-router)#network 199.99.1.0 0.0.0.255 a 0
R2：
R2(config)#int f0/0
R2(config-if)#ip add 199.99.1.2 255.255.255.0
R2(config-if)#no shu
R2(config-if)#exit
R2(config)#int loop0
R2(config-if)#ip add 2.2.2.2 255.255.255.0
R2(config-if)#ip ospf network point-to-point
R2(config-if)#exit
R2(config)#router ospf 100
R2(config-router)#router-id 2.2.2.2
R2(config-router)#network 199.99.1.0 0.0.0.255 a 0
R3：
R3(config)#int f0/0
R3(config-if)#ip add 199.99.1.3 255.255.255.0
R3(config-if)#no shu
R3(config-if)#exit
R3(config)#int loop0
R3(config-if)#ip add 3.3.3.3 255.255.255.0
R3(config-if)#ip ospf network point-to-point
R3(config-if)#exit
R3(config)#router ospf 100
R3(config-router)#router-id 3.3.3.3
R3(config-router)#network 199.99.1.0 0.0.0.255 area 0
配置完成后，使用show ip ospf interface命令查看端口类型：
R1#show ip ospf interface f0/0
FastEthernet0/0 is up, line protocol is up
Internet Address 199.99.1.1/24, Area 0
Process ID 100, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1
Transmit Delay is 1 sec, State DROTHER, Priority 1
Designated Router (ID) 3.3.3.3, Interface address 199.99.1.3
Backup Designated router (ID) 2.2.2.2, Interface address 199.99.1.2
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
oob-resync timeout 40
Hello due in 00:00:01
Supports Link-local Signaling (LLS)
Index 1/1, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 1
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 2, Adjacent neighbor count is 2
Adjacent with neighbor 2.2.2.2 (Backup Designated Router)
Adjacent with neighbor 3.3.3.3 (Designated Router)
Suppress hello for 0 neighbor(s)
R2#show ip ospf interface f0/0
FastEthernet0/0 is up, line protocol is up
Internet Address 199.99.1.2/24, Area 0
Process ID 100, Router ID 2.2.2.2, Network Type BROADCAST, Cost: 1
Transmit Delay is 1 sec, State BDR, Priority 1
Designated Router (ID) 3.3.3.3, Interface address 199.99.1.3
Backup Designated router (ID) 2.2.2.2, Interface address 199.99.1.2
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
oob-resync timeout 40
Hello due in 00:00:06
Supports Link-local Signaling (LLS)
Index 1/1, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 0, maximum is 1
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 2, Adjacent neighbor count is 2
Adjacent with neighbor 1.1.1.1
Adjacent with neighbor 3.3.3.3 (Designated Router)
Suppress hello for 0 neighbor(s)
R3#show ip ospf interface f0/0
FastEthernet0/0 is up, line protocol is up
Internet Address 199.99.1.3/24, Area 0
Process ID 100, Router ID 3.3.3.3, Network Type BROADCAST, Cost: 1
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 3.3.3.3, Interface address 199.99.1.3
Backup Designated router (ID) 2.2.2.2, Interface address 199.99.1.2
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
oob-resync timeout 40
Hello due in 00:00:07
Supports Link-local Signaling (LLS)
Index 1/1, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 1
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 2, Adjacent neighbor count is 2
Adjacent with neighbor 1.1.1.1
Adjacent with neighbor 2.2.2.2 (Backup Designated Router)
Suppress hello for 0 neighbor(s)
不仅可以看到网络类型是BROADCAST，还可以知道端口属于哪个AREA，ROUTER ID是多少，优先级都是默认值1DR,BDR是谁，HELLO/DEAD/WAIT计时器为多少等等。
使用show ip ospf neiighbore命令查看OSPF邻居表：
R1#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
2.2.2.2 1 FULL/BDR 00:00:32 199.99.1.2 FastEthernet0/0
3.3.3.3 1 FULL/DR 00:00:36 199.99.1.3 FastEthernet0/0
R2#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
1.1.1.1 1 FULL/DROTHER 00:00:32 199.99.1.1 FastEthernet0/0
3.3.3.3 1 FULL/DR 00:00:35 199.99.1.3 FastEthernet0/0
R3#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
1.1.1.1 1 FULL/DROTHER 00:00:36 199.99.1.1 FastEthernet0/0
2.2.2.2 1 FULL/BDR 00:00:35 199.99.1.2 FastEthernet0/0
通过上面的输出可以知道R3是DR，R2是BDR，R1为DROther，这是因为R3的router-id最大，R2的次之，R1最小。再使用show ip ospf database查看都有哪些LSA类型：
R1#show ip ospf database
OSPF Router with ID (1.1.1.1) (Process ID 100)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
1.1.1.1 1.1.1.1 353 0x80000002 0x00AF1E 1
2.2.2.2 2.2.2.2 354 0x80000002 0x007153 1
3.3.3.3 3.3.3.3 354 0x80000002 0x003388 1
Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
199.99.1.3 3.3.3.3 354 0x80000001 0x00736F
R2#show ip ospf database
OSPF Router with ID (2.2.2.2) (Process ID 100)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
1.1.1.1 1.1.1.1 371 0x80000002 0x00AF1E 1
2.2.2.2 2.2.2.2 370 0x80000002 0x007153 1
3.3.3.3 3.3.3.3 371 0x80000002 0x003388 1
Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
199.99.1.3 3.3.3.3 371 0x80000001 0x00736F
R3#show ip ospf database
OSPF Router with ID (3.3.3.3) (Process ID 100)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
1.1.1.1 1.1.1.1 379 0x80000002 0x00AF1E 1
2.2.2.2 2.2.2.2 379 0x80000002 0x007153 1
3.3.3.3 3.3.3.3 378 0x80000002 0x003388 1
Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
199.99.1.3 3.3.3.3 378 0x80000001 0x00736F
可以看到只有1类和2类LSA。
然后我们抓取一下R1的debug信息看看：
R1#debug ip ospf adj
OSPF adjacency events debugging is on
R1#
R1#clear ip ospf p
R1#clear ip ospf process
Reset ALL OSPF processes? [no]: y
R1#
*Mar 1 00:13:57.483: OSPF: Interface FastEthernet0/0 going Down
*Mar 1 00:13:57.483: OSPF: 1.1.1.1 address 199.99.1.1 on FastEthernet0/0 is dead, state DOWN
*Mar 1 00:13:57.483: OSPF: Neighbor change Event on interface FastEthernet0/0
*Mar 1 00:13:57.483: OSPF: DR/BDR election on FastEthernet0/0
*Mar 1 00:13:57.487: OSPF: Elect BDR 2.2.2.2
*Mar 1 00:13:57.487: OSPF: Elect DR 3.3.3.3
*Mar 1 00:13:57.487: DR: 3.3.3.3 (Id) BDR: 2.2.2.2 (Id)
*Mar 1 00:13:57.487: OSPF: 2.2.2.2 address 199.99.1.2 on FastEthernet0/0 is dead, state DOWN
*Mar 1 00:13:57.487: %OSPF-5-ADJCHG: Process 100, Nbr 2.2.2.2 on FastEthernet0/0 from FULL to DOWN, Neighbor Down: Interface down or detached
*Mar 1 00:13:57.491: OSPF: Neighbor change Event on interface FastEthernet0/0
*Mar 1 00:13:57.491: OSPF: DR/BDR election on FastEthernet0/0
*Mar 1 00:13:57.491: OSPF: Elect BDR 0.0.0.0
*Mar 1 00:13:57.491: OSPF: Elect DR 3.3.3.3
*Mar 1 00:13:57.495: DR: 3.3.3.3 (Id) BDR: none
*Mar 1 00:13:57.495: OSPF: 3.3.3.3 address 199.99.1.3 on FastEthernet0/0 is dead, state DOWN
*Mar 1 00:13:57.495: %OSPF-5-ADJCHG: Process 100, Nbr 3.3.3.3 on FastEthernet0/0 from FULL to DOWN, Neighbor Down: Interface down or detached
*Mar 1 00:13:57.499: OSPF: Neighbor change Event on interface FastEthernet0/0
*Mar 1 00:13:57.499: OSPF: DR/BDR election on FastEthernet0/0
*Mar 1 00:13:57.499: OSPF: Elect BDR 0.0.0.0
*Mar 1 00:13:57.499: OSPF: Elect DR 0.0.0.0
*Mar 1 00:13:57.499: DR: none BDR: none
*Mar 1 00:13:57.503: OSPF: Remember old DR 3.3.3.3 (id)
*Mar 1 00:13:57.587: OSPF: Interface FastEthernet0/0 going Up
*Mar 1 00:13:57.639: OSPF: 2 Way Communication to 2.2.2.2 on FastEthernet0/0, state 2WAY \\与R2建立邻居关系，形成2 Way。
*Mar 1 00:13:57.639: OSPF: Backup seen Event before WAIT timer on FastEthernet0/0
*Mar 1 00:13:57.643: OSPF: Elect BDR 2.2.2.2
*Mar 1 00:13:57.643: OSPF: Elect DR 2.2.2.2
*Mar 1 00:13:57.643: DR: 2.2.2.2 (Id) BDR: 2.2.2.2 (Id)
*Mar 1 00:13:57.643: OSPF: Send DBD to 2.2.2.2 on FastEthernet0/0 seq 0x1522 opt 0x52 flag 0x7 len 32 \\发送数据库描述报文
*Mar 1 00:13:57.663: OSPF: 2 Way Communication to 3.3.3.3 on FastEthernet0/0, state 2WAY\\与R3建立邻居关系，形成2 Way。
*Mar 1 00:13:57.663: OSPF: Neighbor change Event on interface FastEthernet0/0
*Mar 1 00:13:57.667: OSPF: Elect BDR 2.2.2.2
*Mar 1 00:13:57.667: OSPF: Elect DR 3.3.3.3
*Mar 1 00:13:57.667: DR: 3.3.3.3 (Id) BDR: 2.2.2.2 (Id) \\DR为R3,BDR为R2
*Mar 1 00:13:57.667: OSPF: Send DBD to 3.3.3.3 on FastEthernet0/0 seq 0x18AD opt 0x52 flag 0x7 len 32 \\发送数据库描述报文给DR
*Mar 1 00:13:57.671: OSPF: Remember old DR 2.2.2.2 (id)
*Mar 1 00:13:57.671: OSPF: Neighbor change Event on interface FastEthernet0/0
*Mar 1 00:13:57.671: OSPF: DR/BDR election on FastEthernet0/0
*Mar 1 00:13:57.671: OSPF: Elect BDR 2.2.2.2
*Mar 1 00:13:57.671: OSPF: Elect DR 3.3.3.3
*Mar 1 00:13:57.675: DR: 3.3.3.3 (Id) BDR: 2.2.2.2 (Id)
*Mar 1 00:13:57.711: OSPF: Rcv DBD from 2.2.2.2 on FastEthernet0/0 seq 0x11D0 opt 0x52 flag 0x7 len 32 mtu 1500 state EXSTART \\收到R2的数据库描述报文，转到EXSTART状态
*Mar 1 00:13:57.711: OSPF: NBR Negotiation Done. We are the SLAVE \\MASTER/SLAVE的选取，在此为R2为MASTER，R1为SLAVE。
*Mar 1 00:13:57.715: OSPF: Send DBD to 2.2.2.2 on FastEthernet0/0 seq 0x11D0 opt 0x52 flag 0x0 len 32
*Mar 1 00:13:57.759: OSPF: Rcv DBD from 3.3.3.3 on FastEthernet0/0 seq 0x78A opt 0x52 flag 0x7 len 32 mtu 1500 state EXSTART\\收到R3的数据库描述报文，转到EXSTART状态
*Mar 1 00:13:57.763: OSPF: NBR Negotiation Done. We are the SLAVE \\MASTER/SLAVE的选取，在此为R3为MASTER，R1为SLAVE。
*Mar 1 00:13:57.763: OSPF: Send DBD to 3.3.3.3 on FastEthernet0/0 seq 0x78A opt 0x52 flag 0x0 len 32
*Mar 1 00:13:57.767: OSPF: Rcv DBD from 2.2.2.2 on FastEthernet0/0 seq 0x11D1 opt 0x52 flag 0x3 len 92 mtu 1500 state EXCHANGE \\交换DBD报文，状态转为EXCHANGE。
*Mar 1 00:13:57.771: OSPF: Send DBD to 2.2.2.2 on FastEthernet0/0 seq 0x11D1 opt 0x52 flag 0x0 len 32
*Mar 1 00:13:57.879: OSPF: Rcv DBD from 2.2.2.2 on FastEthernet0/0 seq 0x11D2 opt 0x52 flag 0x1 len 32 mtu 1500 state EXCHANGE
*Mar 1 00:13:57.879: OSPF: Exchange Done with 2.2.2.2 on FastEthernet0/0
*Mar 1 00:13:57.883: OSPF: Send LS REQ to 2.2.2.2 length 36 LSA count 3 \\发送LSR
*Mar 1 00:13:57.883: OSPF: Send DBD to 2.2.2.2 on FastEthernet0/0 seq 0x11D2 opt 0x52 flag 0x0 len 32
*Mar 1 00:13:57.955: OSPF: Rcv DBD from 3.3.3.3 on FastEthernet0/0 seq 0x78B opt 0x52 flag 0x3 len 92 mtu 1500 state EXCHANGE \\交换DBD报文，状态转为EXCHANGE。
*Mar 1 00:13:57.955: OSPF: Send DBD to 3.3.3.3 on FastEthernet0/0 seq 0x78B opt 0x52 flag 0x0 len 32
*Mar 1 00:13:57.987: OSPF: Reset old DR on FastEthernet0/0
*Mar 1 00:13:57.987: OSPF: Build router LSA for area 0, router ID 1.1.1.1, seq 0x80000001
*Mar 1 00:13:57.995: OSPF: Rcv LS UPD from 2.2.2.2 on FastEthernet0/0 length 136 LSA count 3 \\收到LSU
*Mar 1 00:13:57.995: OSPF: Synchronized with 2.2.2.2 on FastEthernet0/0, state FULL *Mar 1 00:13:57.999: %OSPF-5-ADJCHG: Process 100, Nbr 2.2.2.2 on FastEthernet0/0 from LOADING to FULL, Loading Done\\与R2成为FULL状态。
*Mar 1 00:13:57.999: OSPF: Rcv DBD from 3.3.3.3 on FastEthernet0/0 seq 0x78C opt 0x52 flag 0x1 len 32 mtu 1500 state EXCHANGE
*Mar 1 00:13:57.999: OSPF: Exchange Done with 3.3.3.3 on FastEthernet0/0
*Mar 1 00:13:58.003: OSPF: Synchronized with 3.3.3.3 on FastEthernet0/0, state FULL *Mar 1 00:13:58.003: %OSPF-5-ADJCHG: Process 100, Nbr 3.3.3.3 on FastEthernet0/0 from LOADING to FULL, Loading Done\\与R3成为FULL状态。
*Mar 1 00:13:58.003: OSPF: Send DBD to 3.3.3.3 on FastEthernet0/0 seq 0x78C opt 0x52 flag 0x0 len 32
*Mar 1 00:13:58.083: OSPF: Rcv LS UPD from 3.3.3.3 on FastEthernet0/0 length 60 LSA count 1
*Mar 1 00:14:02.583: OSPF: Rcv LS UPD from 2.2.2.2 on FastEthernet0/0 length 64 LSA count 1
*Mar 1 00:14:02.783: OSPF: Rcv LS UPD from 3.3.3.3 on FastEthernet0/0 length 64 LSA count 1
*Mar 1 00:14:02.855: OSPF: Rcv LS UPD from 2.2.2.2 on FastEthernet0/0 length 64 LSA count 1
*Mar 1 00:14:02.859: OSPF: Rcv LS UPD from 3.3.3.3 on FastEthernet0/0 length 64 LSA count 1
*Mar 1 00:14:03.135: OSPF: Rcv LS UPD from 3.3.3.3 on FastEthernet0/0 length 64 LSA count 1
*Mar 1 00:14:03.499: OSPF: Build router LSA for area 0, router ID 1.1.1.1, seq 0x80000003
*Mar 1 00:14:03.671: OSPF: Rcv LS UPD from 3.3.3.3 on FastEthernet0/0 length 64 LSA count 1
红色标记/蓝色注释的部分比较重要，通过红色标记/蓝色注释的部分可以看到整个OSPF邻居建立和选取DR/BDR和交换DBD报文和LSU/LSR/LSAck报文，最终形成FULL状态的全部过程。
实验总结：通过这个简单的实验我们可以知道在广播环境下，OSPF的邻居关系是自动建立的，并且需要有DR/BDR地选取，还可以看到几个特别计时器的设置，hello间隔为10秒，死亡，等待时间为hello时间间隔的4倍40秒。
本文转自loveme2351CTO博客，原文链接：http://blog.51cto.com/loveme23/45808 ，如需转载请自行联系原作者
